ADR 0099: PTO ISA 0.58.3 to 0.58.4 compatibility boundary

Context

Published PTO ISA 0.58.3 is an immutable release identity. The accepted range-command and PE-level programming-model delta is a new working candidate and must not mutate the published 0.58.3 manifest, ABI vectors, encoding evidence, or release provenance. The candidate therefore needs an explicit compatibility boundary and a distinct release identity.

Decision

The working candidate advances from architecture version 0.58.3 to 0.58.4 and uses the repository-convention encoding ABI pto-isa-0.58.4-mode-function-v1. ADR-0097 capacity/M-sharding, ADR-0098 range commands, and the accepted PE-level programming-model delta target 0.58.4.

Published 0.58.3 remains immutable: its release manifest, 0.58.3 ABI vectors, 0.58.3 encoding-totality evidence, release-input registry, and published encoding ABI are not regenerated or rewritten by this candidate. The candidate's release selection uses the published 0.58.3 commit as its baseline and evaluates the accepted candidate NDF set under the new 0.58.4 identity, so the published-NDF-set blocker does not apply across identities.

This decision assigns release compatibility metadata only. It does not authorize V2 release validation, manifest regeneration, tagging, publication, push, or pull-request creation.

Consequences

• 0.58.3 consumers retain the published instruction and ABI contract.
• 0.58.4 is the only working candidate identity for the range-command and PE-level programming-model changes.
• Ordinary PR projections may advance to 0.58.4; published 0.58.3 artifacts remain byte-for-byte unchanged.

Rejected Alternatives

• Mutating the published 0.58.3 manifest or evidence is rejected because a published release identity is immutable.
• Reusing the 0.58.3 architecture version or encoding ABI is rejected because it would make the candidate content-addressed identity ambiguous.